Modulation and Coding Scheme (MCS) Recovery based on CQI Offset

ABSTRACT

Manipulating modulation and coding scheme (MCS) allocation after a communication interruption. A UE device may resume communications with a BS after a communication interruption. First channel quality information may be generated and transmitted to the BS. A first MCS allocation, which may be based at least in part on the first channel quality information, may be received from the BS. Second channel quality information may be generated and transmitted to the BS, where the second channel quality information is modified by an offset configured to modify a second MCS allocation.

PRIORITY CLAIM

The present application claims benefit of priority to U.S. ProvisionalApplication No. 61/667,164 titled “Modulation and Coding Scheme (MCS)Recovery based on CQI Offset” and filed on Jul. 2, 2012, whose inventorsare Tarik Tabet, Navid Damji, Kee-bong Song, S. Aon Mujtaba, YoungjaeKim, Johnson O. Sebeni, and Yuchul Kim, and which is hereby incorporatedby reference in its entirety as thought fully and completely set forthherein.

FIELD

The present application relates to wireless devices, and moreparticularly to a system and method for accelerating MCS recovery aftera communication interruption.

DESCRIPTION OF THE RELATED ART

Wireless communication systems are rapidly growing in usage. Further,wireless communication technology has evolved from voice-onlycommunications to also include the transmission of data, such asInternet and multimedia content. As wireless communication systemsevolve, successive generations of wireless communication technologiestend to be developed. Adoption of a new generation wireless technologymay be a gradual process, during which one or more previous generationsof a similar technology may co-exist with the new generation technology,e.g., for a period of time until the new generation wireless technologyis fully deployed.

Additionally, there exist numerous different wireless communicationtechnologies and standards. Some examples of wireless communicationstandards include GSM, UMTS, LTE, CDMA2000 (e.g., 1xRTT, 1xEV-DO), IEEE802.11 (WLAN or Wi-Fi), IEEE 802.16 (WiMAX), Bluetooth, and others. Someof these standards may serve complementary functions while others maytypically be considered competitors attempting to fulfill similar needsamongst consumers.

In order to provide continuity between generations of wirelesscommunication technologies, in order to provide complementaryfunctionality, and/or for other reasons, it may often be desirable toprovide the ability for a device to communicate using multiple wirelesstechnologies or standards. This may be accomplished by providingseparate RF circuitry for each wireless technology, and/or by providingshared RF circuitry for two or more wireless technologies implemented inthe wireless device.

In some wireless communication systems, in order to provide improvedcommunication between a base station (BS) and wireless user equipment(UE) device, the UE may calculate various metrics that indicate channelquality for feedback to the BS. The BS can use this feedback to adjustits communication with the UE to provide improved communication with theUE. For example, in some systems, these channel quality metrics may beused by the BS to determine code rates and modulation schemes to beassigned to each UE. The code rates and modulation schemes may beselected not only to maximize the throughput to a particular UE, butalso to improve the overall throughput of the base station communicationarea (e.g., the cell) through scheduling. The use of channel qualityindicators may thus allow the BS to more fully exploit the status of thewireless channel to improve communication throughput with variouswireless UE devices.

However, if a wireless device is configured to communicate usingmultiple wireless technologies using a shared RF circuitry, it may benecessary to periodically “tune-away” the shared RF circuitry from useaccording to one of the wireless technologies in order to use the other.This interruption in communication can cause an out-of-sync situationand may disrupt the normal process of the UE providing channel qualityfeedback information to the BS to enable the BS to determine anappropriate code rate and modulation scheme for the UE device. This mayresult in an unwarranted penalty to the downlink (DL) capability of theUE when tuning-back to the original wireless technology.

Furthermore, in long-fade situations, the interrupted communications canresult in a similar out-of-sync situation and/or penalty to the DLcapability on the UE, even in cases where tuning back-and-forth betweenmultiple wireless technologies is not a concern. Accordingly,improvements in wireless communications would be desirable.

SUMMARY OF THE DISCLOSURE

In light of the foregoing and other concerns, embodiments are presentedherein of a method for manipulating downlink throughput (e.g., by way ofmodulation and coding scheme (MCS)) recovery after a communicationinterruption, and a wireless user equipment (UE) device configured toimplement the method. The UE may include one or more radios, includingone or more antennas, for performing wireless communications with basestations (BSs). The UE may also include device logic (which may includea processor and memory medium and/or hardware logic) configured toimplement the method. Embodiments are also presented of a memory medium(e.g., a non-transitory computer accessible memory medium) comprisingprogram instructions executable by a processor to perform part or all ofthe method. The method may be performed as follows.

The UE device may communicate with a first BS according to a firstwireless communication protocol. It may be determined that aninterruption to communication between the UE and the first BS hasoccurred.

The interruption may, as one possibility, be a long fade. In this casethe UE may determine that the interruption is occurring by monitoring(e.g., measuring qualities indicative of) channel conditions, and maydetermine that the interruption (the long fade) has ended when certainconditions are met (e.g., once channel conditions have returned towithin a normal range of conditions).

As another possibility, the UE may be configured to communicate using asecond wireless communication protocol using a radio shared between thefirst and second wireless communication protocols. The communicationinterruption may in this case include the UE device “tuning-away” fromthe first BS in order to communicate with a second base stationaccording to the second wireless communication protocol. In this case,the UE may determine that the interruption has ended when the UE device“tunes back” and resumes communicating with the first BS according tothe first wireless communication protocol.

Upon resuming communicating with the first BS according to the firstwireless communication protocol after the interruption, the UE maygenerate first channel quality information. The first channel qualityinformation might include a CQI value, for example if the first wirelesscommunication protocol is LTE. The first channel quality information maybe generated based at least in part on a first one or more channelquality measurements.

In addition, the first channel quality information may be modified by afirst offset. The first offset may be configured to manipulate adownlink throughput allocation (e.g., as reflected by an MCS allocation)by the first BS, e.g., based on determining that an interruption tocommunication between the UE and the first BS occurred. As onepossibility, the first offset may be a small, fixed offset.Alternatively, the first channel quality information may be basedentirely on the first one or more channel quality measurements. Thefirst channel quality information may be transmitted to the first BS.

The UE may receive first downlink channel information from the first BS.The first downlink channel information may reflect a first allocateddownlink throughput. The first downlink channel information may includea first MCS allocation, which may specify a type of modulation andcoding to be used in downlink communications from the first BS to theUE. A MCS allocation may directly affect the downlink throughput fromthe first BS and the UE, and thus may effectively be considered toreflect the UE's downlink throughput allocation.

The first downlink throughput may be allocated by the BS based at leastin part on the first channel quality information received from the UE.For example, MCS allocations by the first BS may be based at least inpart on channel quality information received from the UE. MCSallocations by the first BS may also be based at least in part on one ormore estimates of recent downlink error rate estimations, such as ablock error rate estimation. The downlink error rate estimations mayinclude estimations from the time period during which communicationswere interrupted, and may thus not accurately represent the currentdownlink error rate.

The UE may subsequently generate second channel quality information. Thesecond channel quality information may include a CQI value, e.g., if thefirst wireless communication protocol is LTE. The second channel qualityinformation may be generated based at least in part on a second one ormore channel quality measurements.

The second channel quality information may also be based on (or may bemodified by) a second offset. The second offset may be generated basedat least in part on the first downlink channel information (e.g., on thefirst one or more channel quality measurements), and may be configuredto modify a future downlink throughput allocation (e.g., as reflected bya MCS allocation). For example, since the first BS may include downlinkerror rate estimations from the time period during which communicationswere interrupted, the MCS allocation selected on that basis may not bethe most appropriate for the actual current channel conditions.Accordingly, it may be desirable to configure the second offset tomanipulate the BS MCS allocation to be more appropriate to the actualcurrent channel conditions.

Thus, the UE may estimate an appropriate first MCS allocation based onthe first channel quality information, and calculate a differencebetween the estimated appropriate first MCS allocation and the actualfirst MCS allocation. This difference may be used as a basis forgenerating the second offset, in order to reduce the difference betweenfuture actual and estimated appropriate MCS allocations.

In addition, the second offset may be generated at least in part basedon an estimation of a downlink error rate, or possibly based oninformation representative of a downlink error rate. For example,downlink data blocks may include cyclic redundancy check (CRC)information, which the UE may use to confirm successful or unsuccessfulreceipt of data via a downlink channel from the first BS. By monitoringhow many such data blocks are successfully received, and how many suchdata blocks are unsuccessfully received, since resuming communicationswith the first BS, and using such information in combination withinformation indicative of a target downlink error rate as part ofgenerating the second offset, the UE may provide a check to ensure thatthe second offset does not over-manipulate the MCS allocation. Forexample, the UE device may only modify the second channel qualityinformation by a second offset if its calculations indicate that thedownlink error rate at the UE is less than (better than) or equal to atarget downlink error rate.

The second channel quality information (e.g., as modified by the secondoffset) may be transmitted to the first BS. The first BS maysubsequently allocate a next MCS for the UE based in part on the secondchannel quality information received. The UE may be configured toiteratively continue to receive future MCS allocations and generatefuture channel quality information including or modified by offsetsconfigured to modify future MCS allocations in a similar manner for acertain amount of time, which amount may be based at least in part on aduration of the communication interruption. After that amount of timehas lapsed, the UE may continue to receive future MCS allocations andgenerate future channel quality information, but those channel qualityinformation transmissions may not include or be modified by any offsets.

BRIEF DESCRIPTION OF THE DRAWINGS

A better understanding of the present subject matter can be obtainedwhen the following detailed description of the embodiments is consideredin conjunction with the following drawings.

FIG. 1 illustrates an exemplary (and simplified) wireless communicationsystem;

FIG. 2 illustrates a base station in communication with user equipment;

FIG. 3 illustrates an exemplary block diagram of a UE;

FIG. 4 is a flowchart diagram illustrating a method for a acceleratingMCS recovery after a communication interruption;

FIG. 5 is a system diagram illustrating communications between a BS anda UE;

FIG. 6 is a flowchart illustrating an exemplary CQI selection processfor a period of time after a tune-away or fade;

FIG. 7 is a timing diagram illustrating timing of the exemplary CQIselection process illustrated in FIG. 6;

FIG. 8 is a data flow diagram illustrating an aspect of the exemplaryCQI selection process illustrated in FIG. 6; and

FIG. 9 illustrates an exemplary table which may be used for CQI to MCSlook-up.

While the features described herein are susceptible to variousmodifications and alternative forms, specific embodiments thereof areshown by way of example in the drawings and are herein described indetail. It should be understood, however, that the drawings and detaileddescription thereto are not intended to be limiting to the particularform disclosed, but on the contrary, the intention is to cover allmodifications, equivalents and alternatives falling within the spiritand scope of the subject matter as defined by the appended claims.

DETAILED DESCRIPTION OF THE EMBODIMENTS Acronyms

The following acronyms are used in the present patent application:

PER: Packet Error Rate

BLER: Block Error Rate (same as Packet Error Rate)

BER: Bit Error Rate

CRC: Cyclic Redundancy Check

UL: Uplink

DL: Downlink

SNR: Signal to Noise Ratio

SIR: Signal to Interference Ratio

SINR: Signal to Interference-and-Noise Ratio

Tx: Transmission (or Transmit)

Rx: Reception (or Receive)

UE: User Equipment

UMTS: Universal Mobile Telecommunication System

LTE: Long Term Evolution

PDSCH: Physical Downlink Shared Channel

Terms

The following is a glossary of terms used in the present application:

Memory Medium—Any of various types of memory devices or storage devices.The term “memory medium” is intended to include an installation medium,e.g., a CD-ROM, floppy disks, or tape device; a computer system memoryor random access memory such as DRAM, DDR RAM, SRAM, EDO RAM, RambusRAM, etc.; a non-volatile memory such as a Flash, magnetic media, e.g.,a hard drive, or optical storage; registers, or other similar types ofmemory elements, etc. The memory medium may include other types ofmemory as well or combinations thereof. In addition, the memory mediummay be located in a first computer system in which the programs areexecuted, or may be located in a second different computer system whichconnects to the first computer system over a network, such as theInternet. In the latter instance, the second computer system may provideprogram instructions to the first computer for execution. The term“memory medium” may include two or more memory mediums which may residein different locations, e.g., in different computer systems that areconnected over a network.

Carrier Medium—a memory medium as described above, as well as a physicaltransmission medium, such as a bus, network, and/or other physicaltransmission medium that conveys signals such as electrical,electromagnetic, or digital signals.

Programmable Hardware Element—includes various hardware devicescomprising multiple programmable function blocks connected via aprogrammable interconnect. Examples include FPGAs (Field ProgrammableGate Arrays), PLDs (Programmable Logic Devices), FPOAs (FieldProgrammable Object Arrays), and CPLDs (Complex PLDs). The programmablefunction blocks may range from fine grained (combinatorial logic or lookup tables) to coarse grained (arithmetic logic units or processorcores). A programmable hardware element may also be referred to as“reconfigurable logic”.

Computer System—any of various types of computing or processing systems,including a personal computer system (PC), mainframe computer system,workstation, network appliance, Internet appliance, personal digitalassistant (PDA), television system, grid computing system, or otherdevice or combinations of devices. In general, the term “computersystem” can be broadly defined to encompass any device (or combinationof devices) having at least one processor that executes instructionsfrom a memory medium.

User Equipment (UE) (or “UE Device”)—any of various types of computersystems devices which are mobile or portable and which performs wirelesscommunications. Examples of UE devices include mobile telephones orsmart phones (e.g., iPhone™, Android™-based phones), portable gamingdevices (e.g., Nintendo DS™, PlayStation Portable™, Gameboy Advance™,iPod™), laptops, tablets (e.g., iPad™, Android™-based tablets), PDAs,portable Internet devices, music players, data storage devices, or otherhandheld devices, etc. In general, the term “UE” or “UE device” can bebroadly defined to encompass any electronic, computing, and/ortelecommunications device (or combination of devices) which is easilytransported by a user and capable of wireless communication.

Base Station—The term “Base Station” has the full breadth of itsordinary meaning, and at least includes a wireless communication stationinstalled at a fixed location and used to communicate as part of awireless telephone system or radio system.

Channel—a medium used to convey information from a sender (transmitter)to a receiver. It should be noted that since the definition of the term“channel” may differ according to different wireless protocols, the term“channel” as used herein should be considered as being used in a mannerthat is consistent with the standard of the type of device withreference to which the term is used. In some standards, channel widthsmay be variable (e.g., depending on device capability, band conditions,etc.). For example, LTE may support scalable channel bandwidths from 1.4MHz to 20 MHz. In contrast, WLAN channels may be 22 MHz wide whileBluetooth channels may be 1 Mhz wide. Other protocols and standards mayinclude different definitions of channels. Furthermore, some standardsmay define and use multiple types of channels, e.g., different channelsfor uplink or downlink and/or different channels for different uses suchas data, control information, etc.

Automatically—refers to an action or operation performed by a computersystem (e.g., software executed by the computer system) or device (e.g.,circuitry, programmable hardware elements, ASICs, etc.), without userinput directly specifying or performing the action or operation. Thusthe term “automatically” is in contrast to an operation being manuallyperformed or specified by the user, where the user provides input todirectly perform the operation. An automatic procedure may be initiatedby input provided by the user, but the subsequent actions that areperformed “automatically” are not specified by the user, i.e., are notperformed “manually”, where the user specifies each action to perform.For example, a user filling out an electronic form by selecting eachfield and providing input specifying information (e.g., by typinginformation, selecting check boxes, radio selections, etc.) is fillingout the form manually, even though the computer system must update theform in response to the user actions. The form may be automaticallyfilled out by the computer system where the computer system (e.g.,software executing on the computer system) analyzes the fields of theform and fills in the form without any user input specifying the answersto the fields. As indicated above, the user may invoke the automaticfilling of the form, but is not involved in the actual filling of theform (e.g., the user is not manually specifying answers to fields butrather they are being automatically completed). The presentspecification provides various examples of operations beingautomatically performed in response to actions the user has taken.

FIGS. 1 and 2—Communication System

FIG. 1 illustrates an exemplary (and simplified) wireless communicationsystem. It is noted that the system of FIG. 1 is merely one example of apossible system, and embodiments may be implemented in any of varioussystems, as desired.

As shown, the exemplary wireless communication system includes a basestation 102 which communicates over a transmission medium with one ormore user devices 106-1 through 106-N. Each of the user devices may bereferred to herein as a “user equipment” (UE). Thus, the user devicesare referred to as UEs or UE devices.

The base station 102 may be a base transceiver station (BTS) or cellsite, and may include hardware that enables wireless communication withthe UEs 106A through 106N. The base station 102 may also be equipped tocommunicate with a network 100. Thus, the base station 102 mayfacilitate communication between the UEs and/or between the UEs and thenetwork 100. The communication area (or coverage area) of the basestation may be referred to as a “cell.” The base station 102 and the UEsmay be configured to communicate over the transmission medium using anyof various wireless communication technologies such as GSM, CDMA, WLL,WAN, WiFi, WiMAX, etc.

UE 106 may be capable of communicating using multiple wirelesscommunication standards. For example, a UE 106 might be configured tocommunicate using either of a 3GPP cellular communication standard (suchas LTE) or a 3GPP2 cellular communication standard (such as a cellularcommunication standard in the CDMA2000 family of cellular communicationstandards). Thus, the UE 106 might be configured to communicate withbase station 102 according to a first cellular communication standard(e.g., LTE) and might also be configured to communicate with other basestations according to a second cellular communication standard (e.g.,one or more CDMA2000 cellular communication standards). Base station 102and other similar base stations operating according to the same or adifferent cellular communication standard may thus be provided as anetwork of cells, which may provide continuous or nearly continuousoverlapping service to UE 106 and similar devices over a wide geographicarea via one or more cellular communication standards.

The UE 106 might also or alternatively be configured to communicateusing WLAN, Bluetooth, one or more global navigational satellite systems(GNSS, e.g., GPS or GLONASS), one and/or more mobile televisionbroadcasting standards (e.g., ATSC-M/H or DVB-H), etc. Othercombinations of wireless communication standards (including more thantwo wireless communication standards) are also possible.

FIG. 2 illustrates user equipment 106 (e.g., one of the devices 106-1through 106-N) in communication with the base station 102. The UE 106may be a device with wireless network connectivity such as a mobilephone, a hand-held device, a computer or a tablet, or virtually any typeof wireless device.

The UE may include a processor that is configured to execute programinstructions stored in memory. The UE may perform any of the methodembodiments described herein by executing such stored instructions.Alternatively, or in addition, the UE may include a programmablehardware element such as an FPGA (field-programmable gate array) that isconfigured to perform any of the method embodiments described herein, orany portion of any of the method embodiments described herein.

The UE 106 may be configured to communicate using any of multiplewireless communication protocols. For example, the UE 106 may beconfigured to communicate using two or more of CDMA 2000, LTE, WLAN, orGNSS. Other combinations of wireless communication standards are alsopossible.

The UE 106 may include one or more antennas for communicating using oneor more wireless communication protocols. The UE 106 may share one ormore parts of a receive and/or transmit chain between multiple wirelesscommunication standards; for example, the UE 106 might be configured tocommunicate using either of CDMA 2000 (1xRTT/1xEV-DO) or LTE using asingle shared radio. The shared radio may include a single antenna, ormay include multiple antennas (e.g., for MIMO) for performing wirelesscommunications. Alternatively, the UE 106 may include separate transmitand/or receive chains (e.g., including separate antennas and other radiocomponents) for each wireless communication protocol with which it isconfigured to communicate. As another alternative, the UE 106 mayinclude one or more radios which are shared between multiple wirelesscommunication protocols, and one or more radios which are usedexclusively by a single wireless communication protocol. For example, inone set of embodiments, the UE 106 may include a shared radio forcommunicating using either of LTE or 1xRTT, and separate radios forcommunicating using each of Wi-Fi and Bluetooth. Other configurationsare also possible.

The UE 106 may also be configured to generate channel qualityinformation that may be provided back to the base station 102. The basestation 102 may use the channel quality information received from one ormore UEs 106 to adjust its communications with the respective UE 106, orpossibly other UEs 106. For example, the base station 102 might receiveand utilize channel quality information from multiple UEs 106 to adjustits communication scheduling among the various UEs within its coveragearea (or cell). The BS 102 may utilize channel quality information indetermining a modulation and coding scheme combination for the UE 106based at least in part on the channel quality information received fromthe UE 106, such as further described hereinbelow.

FIG. 3—Exemplary Block Diagram of a UE

FIG. 3 illustrates an exemplary block diagram of a UE 106. As shown, theUE 106 may include a system on chip (SOC) 300, which may includeportions for various purposes. For example, as shown, the SOC 300 mayinclude processor(s) 302 which may execute program instructions for theUE 106 and display circuitry 304 which may perform graphics processingand provide display signals to the display 340. The processor(s) 302 mayalso be coupled to memory management unit (MMU) 340, which may beconfigured to receive addresses from the processor(s) 302 and translatethose addresses to locations in memory (e.g., memory 306, read onlymemory (ROM) 350, NAND flash memory 310) and/or to other circuits ordevices, such as the display circuitry 304, radio 330, connector I/F320, and/or display 340. The MMU 340 may be configured to perform memoryprotection and page table translation or set up. In some embodiments,the MMU 340 may be included as a portion of the processor(s) 302.

As shown in FIG. 3, ROM 350 may include a bootloader, which may beexecuted by the processor(s) 302 during boot up or initialization. Asalso shown, the SOC 300 may be coupled to various other circuits of theUE 106. For example, the UE 106 may include various types of memory(e.g., including NAND flash 310), a connector interface 320 (e.g., forcoupling to the computer system), the display 340, and wirelesscommunication circuitry (e.g., for LTE, CDMA2000, Bluetooth, WiFi,etc.).

The UE device 106 may include at least one antenna, and possiblymultiple antennas, for performing wireless communication with basestations and/or other devices. For example, the UE device 106 may useantenna 335 to perform the wireless communication. As noted above, theUE may be configured to communicate wirelessly using multiple wirelesscommunication standards.

As described herein, the UE 106 may include hardware and softwarecomponents for implementing a method generating a channel qualityfeedback offset according to embodiments of this disclosure. FIG. 5 andthe description provided with respect thereto relate to one such methodaccording to one set of embodiments.

The processor 302 of the UE device 106 may be configured to implementpart or all of the methods described herein, e.g., by executing programinstructions stored on a memory medium (e.g., a non-transitorycomputer-readable memory medium). In other embodiments, processor 302may be configured as a programmable hardware element, such as an FPGA(Field Programmable Gate Array), or as an ASIC (Application SpecificIntegrated Circuit).

FIG. 4—Flowchart

FIG. 4 is a flowchart diagram illustrating a method for manipulatingdownlink throughput allocation after a communication interruption thatmay be performed by a wireless UE device (such as UE 106). The methodshown in FIG. 4 may be used in conjunction with any of the computersystems or devices shown in the above Figures, among other devices. Invarious embodiments, some of the method elements shown may be performedconcurrently, in a different order than shown, or may be omitted.Additional method elements may also be performed as desired. As shown,this method may operate as follows.

The UE device may initially communicate with a first base station (BS)according to a first wireless communication protocol. At some point, aninterruption to communication between the UE and the first BS may occur.The interruption to communication may be caused by any of a number ofreasons. In some embodiments, the interruption may be a “discontinuousinterruption”. In this context, the term discontinuous interruption isused to refer to an interruption which is not expected to have anycontinuing effect on channel conditions after the interruption is ended.For example, the discontinuous interruption may have been caused by aone-time natural or man-made event affecting channel conditions, or mayhave been caused by the UE device actively interrupting communications.

For example, the interruption might be a long fade. In this case the UEmay determine that the interruption is occurring by monitoring (e.g.,measuring qualities indicative of) channel conditions, and may determinethat the interruption (the long fade) has ended when certain conditionsare met (e.g., once channel conditions have returned to within a normalrange of conditions). In many cases, after a long fade is over, theremay be substantially no residual effects on channel conditions, and so along fade may in some cases be considered a discontinuous interruption.

As another possibility, as noted above, a discontinuous interruption maybe caused by the UE device actively interrupting communications. Forexample, the UE may also be configured to communicate using a secondwireless communication protocol using a radio shared between the firstand second wireless communication protocols. The communicationinterruption may in this case include the UE device “tuning-away” fromthe first BS in order to communicate with a second base stationaccording to the second wireless communication protocol. In this case,the UE may determine that the interruption has ended when the UE device“tunes-back” and resumes communicating with the first BS according tothe first wireless communication protocol. In this case, having“tuned-away” may not have any effect on the channel conditions presentonce the UE “tunes-back’, and so this may be considered a discontinuousinterruption.

In 402, the UE device may resume communicating with the first BSaccording to the first wireless communication protocol after theinterruption.

In 404, the UE may generate first channel quality information. The firstchannel quality information may include a CQI value, e.g., if the firstwireless communication protocol is LTE. Any number of variations,alternatives, and/or supplements to CQI values may also or alternativelybe used (e.g., in different communication systems, such as CDMA2000 orWiMAX), as desired. The first channel quality information may begenerated based at least in part on a first one or more channel qualitymeasurements, such as signal to noise ratio (SNR) or signal tointerference plus noise ratio (SINR), spectral efficiency (SE)estimation, and/or any of various other measurements or estimationsindicative of channel quality.

In addition, if desired, the first channel quality information may bemodified by a first offset. The first offset may be configured tomanipulate a downlink throughput allocation (e.g., as reflected by a MCSallocation) by the first BS, e.g., based on determining that aninterruption to communication between the UE and the first BS occurred.As one example, the first offset may be a small, fixed offset.Alternatively, the first channel quality information may be basedentirely on the first one or more channel quality measurements, ifdesired. The first channel quality information may be transmitted to thefirst BS.

In 406, the UE may receive first downlink channel information from thefirst BS. The first downlink channel information may reflect a firstallocated downlink throughput. For example, the first downlink channelinformation may include a first MCS allocation, which may specify a typeof modulation and coding to be used in downlink communications from thefirst BS to the UE. A MCS allocation may directly affect the downlinkthroughput from the first BS and the UE, and thus may effectively beconsidered to reflect the UE's downlink throughput allocation. Forexample, in LTE, any of QPSK, 16QAM, or 64QAM modulation schemes may beused, in combination with a variety of coding rates. Each combinationmay result in a different effective throughput between the UE and thefirst BS, depending on the error rate. Ideally, the BS may select an MCSallocation which maximizes throughput (possibly depending on QoS orservice terms for the UE device) while maintaining a reasonable errorrate. Note that other types of downlink channel information reflectiveof allocated downlink throughput may be used instead of or in additionto a MCS if desired.

The first downlink throughput may be allocated by the BS based at leastin part on the first channel quality information received from the UE.For example, MCS allocations by the first BS may be based at least inpart on channel quality information received from the UE. MCSallocations by the first BS may also be based at least in part on one ormore estimates of recent downlink error rate estimations, such as one ormore block error rate estimations. Ideally, the BS estimation of recentdownlink error rate would reflect actual channel conditions over arelevant period of time. However, if the downlink error rate estimationsinclude estimations from the time period during which communicationswere interrupted, they may reflect channel conditions over a period oftime of which at least part may not reflect current channel conditions.

For example, the UE might not report any information relating to successor failure rates (e.g., ACK/NACK information) of downlink data duringthe time period during which communications were interrupted. Sodownlink error rate estimation by the BS during that period of time mayincrease, since the BS may assume the lack of success or failure ratereporting to be an indicator of failed downlink communication. Thus, ifthe lack of success or failure rate reporting is a result of adiscontinuous communication interruption and not a result of ongoingpoor channel conditions, use of downlink error rate estimations by theBS which include at least part of the time period during whichcommunications were interrupted may not reflect actual channelconditions, e.g., once the UE tunes back.

In 408, the UE may generate second channel quality information. Muchlike the first channel quality information, the second channel qualityinformation may include a CQI value (e.g., if the first wirelesscommunication protocol is LTE), and/or any other type of channel qualityinformation. The second channel quality information may be generatedbased at least in part on a second one or more channel qualitymeasurements, which may include any of a variety of measurements orestimations indicative of channel quality, in a similar manner as thefirst one or more channel quality measurements.

The second channel quality information may also be based on (or may bemodified by) a second offset. The second offset may be generated basedat least in part on the first downlink channel information (e.g., on thefirst one or more channel quality measurements), and may be configuredto modify a future downlink throughput allocation (e.g., as reflected bya MCS allocation). For example, since the first BS may include downlinkerror rate estimations from the time period during which communicationswere interrupted, the MCS allocation selected on that basis may not bethe most appropriate for the actual current channel conditions.Accordingly, it may be desirable to configure the second offset tomanipulate the BS MCS allocation to be more appropriate to the actualcurrent channel conditions.

Thus, the UE may estimate an appropriate first MCS allocation based onthe first channel quality information, and calculate a differencebetween the estimated appropriate first MCS allocation and the actualfirst MCS allocation. This difference may be used as a basis forgenerating the second offset, e.g., in order to reduce the differencebetween future actual and estimated appropriate MCS allocations.

In addition, the second offset may be generated at least in part basedon an estimation of a downlink error rate, or possibly based oninformation representative of a downlink error rate. For example,downlink data blocks may include cyclic redundancy check (CRC)information, which the UE may use to confirm successful or unsuccessfulreceipt of data via a downlink channel from the first BS. By monitoringhow many such data blocks are successfully received, and how many suchdata blocks are unsuccessfully received, since resuming communicationswith the first BS, and using such information in combination withinformation indicative of a target downlink error rate as part ofgenerating the second offset, the UE may provide a check to ensure thatthe second offset does not over-manipulate the MCS allocation. Forexample, the UE device might only modify the second channel qualityinformation by a second offset if its calculations indicate that thedownlink error rate at the UE is less than (better than) or equal to atarget downlink error rate. Downlink error rate estimations and targetdownlink error rate may also or alternatively be utilized in differentways in generating the second offset, as desired. The second channelquality information (e.g., as modified by the second offset) may betransmitted to the first BS.

In 410, the UE may receive second downlink channel information. Forexample, the BS may allocate and transmit a second MCS to the UE. Thesecond MCS may be selected by the BS based in part on the second channelquality information received from the UE. Since the second channelquality information may include the second offset, the second MCS maymore closely approach an estimated appropriate second MCS (e.g., whichmay be generated in a similar manner as described above with respect tothe estimated appropriate first MCS) than the first MCS may approach theestimated appropriate first MCS.

The UE may be configured to iteratively continue to receive future MCSallocations and generate future channel quality information including ormodified by offsets configured to modify future MCS allocations in asimilar manner for a certain amount of time. The amount of time forwhich this may occur may be based at least in part on a duration of thecommunication interruption. After that amount of time has lapsed, the UEmay continue to receive future MCS allocations and generate futurechannel quality information, but those channel quality informationtransmissions may not include or be modified by offsets such as thosedescribed hereinabove.

Note that the UE may not need to modify the channel quality informationby an offset in all cases, even within the amount of time for which theUE is configured to do so. For example, if an estimated appropriate MCSmatches an actual MCS, there may be no need to manipulate a next channelquality information report, as the actual MCS may be the appropriate MCSfor the channel conditions which the UE is experiencing at that time.

Thus, by utilizing the method of FIG. 4 as provided above according tovarious embodiments, a UE may advantageously rapidly recover from and/oravoid unwarranted MCS penalties imposed by the BS as a result of adiscontinuous interruption to communication between the BS and the UE.

FIGS. 5-9—Exemplary Implementation

FIGS. 5-9 illustrate aspects of a selected exemplary implementation ofthe method of FIG. 4. While numerous specific details of the exemplaryset of embodiments of FIGS. 5-9 are provided herein below by way ofexample, it will be recognized by those of skill in the art that anynumber of variations on or alternatives to the specific details of theexemplary embodiments of FIGS. 5-9 may be implemented if desired, andthat accordingly the description provided with respect thereto shouldnot be considered limiting to the disclosure as a whole.

In the exemplary set of embodiments of FIGS. 5-9, a UE device may beconfigured to communicate with base stations via the LTE wirelesscommunication protocol. Base stations that operate according to LTE mayalso be referred to herein as “eNodeBs” or “eNBs”. The UE device mayalso be configured to communicate with base stations using anothercellular communication protocol, such as CDMA2000 (e.g., including 1xRTTand/or 1xEV-DO), though this may not be necessary. Note that it may bethe case that base stations may either operate according to LTE oraccording to CDMA2000, but not both.

As part of the LTE protocol, the UE device may occasionally(periodically or aperiodically) send channel state feedback reports,which may include information reflecting the quality of the downlinkchannel state at the receiver. One example of such a metric which isused in LTE is a channel quality indicator (CQI). The CQI is defined inLTE as a value between 0 and 15 that may be reflective primarily ofchannel quality. It may be based on channel estimation, noiseestimation, signal-to-noise ratio (SNR) estimation,signal-to-interference-plus-noise ratio (SINR) estimation, and/or otherfactors, depending on the implementation. The eNB may estimate (e.g.,using a mapping table) downlink (DL) SINR at the UE based on the CQIreported by the UE. Another example of a channel state metric that maybe used in some embodiments is rank indication (RI), which may be anindicator of the number of transmission layers that the UE can supportto optimize throughput.

Another element of the LTE protocol includes the use of positiveacknowledgement (“ACK”) and negative acknowledgement (“NACK”) messages.The UE may confirm successful receipt of a block of data (e.g., atransport block) by transmitting an ACK message to the eNB. Similarly,the UE may inform the eNB of failed receipt of a block of data bytransmitting a NACK message to the eNB. The UE may make use of cyclicredundancy check (CRC) suffixes in the data blocks in determiningsuccessful or unsuccessful receipt of each data block. The ACK and NACKmessages may be used in turn by the eNB to estimate a DL block errorrate (BLER) at the UE.

A process referred to generally in wireless networks as link adaptationmay be used to select an appropriate modulation and coding scheme (MCS)and power for a UE device to achieve a target quality of service (QoS)and BLER. In particular, an aspect of this process referred to as outerloop link adaptation may be used by the eNB to determine an MCS for a UEbased on the UE's reported CQI (and possibly RI) and an estimated DLBLER. The determination may be based on one or more mapping tables, suchas a table mapping CQI to MCS, such as shown in FIG. 9, and/or a tablemapping the effects of changes in RI to MCS.

FIG. 5 is a system diagram illustrating a BS 502 and a UE device 506engaged in such outer loop link adaptation related communications. Asshown, the BS 502 and the UE 506 may each include one or more antennasand various functional blocks for performing wireless communications,including functional blocks for generating ACK/NACK messages andperforming CQI estimation at the UE 506, and functional blocks forestimating DL BLER, estimating DL SINR, selecting an MCS, and allocatingDL resources to the UE 506 at the BS 502. Those skilled in the art willrecognize that UE 506 and BS 502 may typically include numerous othersystem components, which are not shown in FIG. 5 in order to avoidobscuring the details of the exemplary implementation.

As shown, the UE 506 may generate ACK/NACK messages, CQI measurements,and RI measurements and transmit such information via an uplink channel.The BS 502 may use the ACK/NACK messages to estimate the DL BLER (e.g.,based on how many blocks were received successfully vs. unsuccessfully),and may use the CQI to estimate the DL SINR (e.g., using a predefinedmapping). The BS 502 may then select an MCS for the UE 506 based on theDL BLER, the DL SINR, and a target BLER.

For example, according to one set of embodiments, the estimated BLER andthe target BLER may be used to select an offset to the DL SINR.Depending on whether the measured BLER is lower (better) or higher(worse) than the target BLER, the offset may be positive or negativerespectively. The offset may be applied to the estimated DL SINR, whichmay then be used to select the MCS based on a SINR-MCS mapping.

The UE 506 may then be provided with the MCS allocation and DLscheduling information from the BS 502 via the DL channel, and maysubsequently receive further data from the BS 502 via the DL channelaccording to the allocated MCS and scheduling information. The UE 506may subsequently perform further CQI measurements and generate furtherACK/NACK messages based on the information received via the DL channel,and transmit such information to the BS 502 via the UL channel,providing a steady-state cycle in which MCS may be dynamically adjustedin accordance with varying channel conditions.

This system works well as long as there are no discontinuousinterruptions in communications between the UE 506 and the BS 502.However, in a situation in which a long fade occurs, the interruption incommunication between the UE 506 and the BS 502 can result in the UE 506losing synchronization with the BS 502, causing the estimation of DLBLER at the BS 502 to grow to a large value (possibly 100%).

Additionally, some UEs are configured to use a single radio tocommunicate according to multiple cellular communication protocols; forexample, according to one set of embodiments, UE 506 may be configuredto communicate using either of LTE or CDMA2000 using a single radio. Inthis case, it may be common for the UE 506 to usually use one of thecellular communication protocols (e.g., LTE), but to “tune-away” theradio occasionally to use the other cellular communication protocol(e.g., CDMA2000 1xRTT), e.g., to listen to a paging channel. During sucha “tune-away”, the connection of the UE 506 with the original cellularcommunication protocol may be interrupted. Similar to a long fade, thismay cause a loss of synchronization between the UE 506 and the BS 502may result in the BS 502 estimating the DL BLER of the UE 506 to be veryhigh (again, possibly 100%).

Thus, in certain cases in which a discontinuous interruption incommunications between the UE 506 and the BS 502 occurs, the BS 502 mayallocate to the UE 502 an MCS with a lower throughput than is warrantedby the current channel conditions, because of a high DL BLER estimateduring the interruption. This may in turn result in the UE 502 obtaininga lower (better) DL BLER than the target DL BLER, at the cost of lowerthan ideal DL throughput.

In such cases, in which it is known at the UE 506 that the interruptionin communications is not reflective of current channel conditions (e.g.,because it was caused by the UE 506 tuning away, or because the UE 506detects that the fade has ended), it may be desirable for the UE 506 tomake one or more adjustments to the measurements on the basis of whichthe BS 502 will allocate the MCS. This may allow the UE 506 to morequickly obtain an MCS with which the UE 506 may achieve both its targetQoS and BLER.

An example of such an adjustment might include a CQI offset. Because theCQI is used by the BS 502 to estimate DL SINR, which in turn is used bythe BS 502 to select the MCS for the UE 506, if the UE 506 modifies itsmeasured CQI by a CQI offset, this will in turn directly and predictablyaffect the MCS which will be allocated to the UE 506. If the CQI offsetis selected to account for the difference between the MCS allocated tothe UE 506 by the BS 502 and an MCS which would reflect current DL BLERand SINR, the next MCS should more accurately reflect current channelconditions.

Thus, in the exemplary embodiment of FIGS. 5-9, the UE 506 may beconfigured to perform such CQI modification in order to obtainappropriate MCS allocation more quickly after an interruption incommunication between the UE 506 and the BS 502. The UE 506 may performa method implementing such CQI modification for a period of time afterdetermining that the UE 506 has “returned” from an interruption incommunication with the BS 502. FIG. 6 is a flowchart diagramillustrating the steps of such a method according to one set ofembodiments. FIG. 7 is a timing diagram illustrating the time framecorresponding to the method of FIG. 6. FIG. 8 is a diagram illustratingfunctional blocks that may be used in generating a CQI offset inconjunction with the method of FIG. 6. The method may be performed asfollows.

Initially, the UE 506 may “tune-back” to LTE after “tuning-away” for aperiod of time, e.g., to check for 1xRTT paging messages. At this time atimer (“T”) may be initiated, with an initial condition of T=0.

For an initial period of time after tuning back, the UE 506 may not yethave received an MCS, and so may not know to what degree (if any) the BS502 will “penalize” (relative to actual channel conditions) the UE 506with its MCS allocation. Accordingly, for a first period of time (e.g.,from T=0 until T=T_(WAIT)), the UE 506 may generate a CQI value in afirst manner.

The first manner may include measuring the CQI as normal (referred to as“CQI_(no-offset)”), adding a nominal offset of +1, and transmitting tothe BS 502 the lesser of the resulting CQI value or the maximum possibleCQI value (e.g., 15) in the CQI report. Alternatively the first mannermay include simply measuring CQI_(no-offset) and transmitting that valuewithout any offset in the CQI report. By using a low offset or no offsetin this manner, the UE 506 may avoid over-compensating for the expectedMCS penalty, which might result in the UE 506 being allocated an MCS forwhich the actual BLER would be larger than the target BLER.

The value of T_(WAIT) may be selected such as to allow sufficient timefor an initial CQI report by the UE 506 to be received and take effectat the BS 506 (e.g., at a scheduler at the BS 506). For example, asshown in FIG. 7, according to some embodimentsT_(WAIT)=T_(First-CQI)+ΔT, where T_(First-CQI) is the time of occurrenceof the first CQI report after tuning-back, and ΔT is a time delay toaccommodate the time needed for the first CQI to take effect at the BS506.

Once the initial CQI report has had time to take effect at the BS 506(e.g., and the UE 506 has received an MCS from the BS 502), it may beappropriate for the UE 506 to adjust its CQI reports if the MCSallocated by the BS 502 does not reflect current channel conditions.Thus, as shown in FIGS. 6 and 7, during a second period of time (e.g.,from T=T_(WAIT) until T=T_(WAIT)+δ, the UE 506 may generate a CQI valuein a second manner).

The second manner may include measuring CQI_(no-offset), adding a CQIoffset (“a”) whose derivation according to various embodiments will bedescribed further subsequently herein, and transmitting to the BS 502the lesser of the resulting CQI value or the maximum possible CQI value(e.g., 15) in the CQI report.

The CQI offset α may be selected in a manner intended to bring the MCSallocation in line with the current channel conditions. Accordingly, theprocess for generating the CQI offset α may, in some embodiments,include estimating what the MCS would be under the current channelconditions, determining the difference between this MCS estimate and theactual allocated MCS, and using this as a basis for determining the CQIoffset α.

More particularly, as shown in FIG. 8, the UE 506 may use as inputs forcalculation of the CQI offset α the values CQI_(no-offset), results ofCRC detections of DL transmissions (e.g., PDSCH transmissions) sincetune-back, a BLER target, and the actual MCS allocated to the UE 506 bythe BS 502 over the DL channel. The CQI_(no-offset) value may be mappedto an MCS estimate in the CQI-MCS Mapping block, which may be passed tothe CQI offset determination block along with the other inputs, asshown. The selected offset may be added to CQI_(no-offset), and thelesser of the result or the maximum possible CQI value may be used inthe CQI report.

It may generally be desirable that the size of the offset depends on thesize of the difference between the allocated and estimated MCS. Aspreviously noted, MCS values may be selected based on an interpretationof CQI as representative of SINR at the UE. And as also previouslynoted, the BS may apply, to the SINR it estimates based on the CQIreport, an SINR offset based on a BLER estimate generated by the BS. InLTE, a 1 dB SINR step corresponds to one MCS step. A CQI stepcorresponds to 2 dB SINR. Thus, to offset the difference between theallocated and estimated MCS, a general strategy may be to divide thedifference by two and apply the result as the CQI offset.

However, the exact method used to generate the CQI offset α from thesevalues may vary depending on the implementation. For example, certainchecks and limits may be applied to the calculation, depending on howaggressively it is desired to manipulate the MCS allocation. Forexample, if the estimated BLER does not meet or beat the target BLER, itmay not be desirable to manipulate the MCS allocation. In addition, itmay be desirable to limit the CQI offset α to a maximum possible value,in order to avoid overshooting the ideal MCS. In general, if theallocated MCS does not match the estimated MCS and the estimated BLER(based on the CRC results) meets or beats the target BLER, this may bean indication that an offset should be generated to manipulate theallocated MCS to more closely reflect the actual current channelconditions.

According to one set of embodiments, the CQI offset α may be calculatedas follows:

let[x]⁺ = max (0, x) $1_{\{{CRCfail}\}} = \{ {{\begin{matrix}1 & {{if}\mspace{14mu} {CRC}\mspace{14mu} {fails}} \\0 & {otherwise}\end{matrix}1_{\{{CRCpass}\}}} = \{ {{\begin{matrix}1 & {{if}\mspace{14mu} {CRC}\mspace{14mu} {passes}} \\0 & {otherwise}\end{matrix}{then}\alpha} = \{ {{\begin{matrix}1 & {{if}\mspace{14mu} {no}\mspace{14mu} {DL}\mspace{14mu} {TX}\mspace{14mu} {scheduled}\mspace{14mu} {since}\mspace{14mu} {tune}\text{-}{back}} \\\lambda & {otherwise}\end{matrix}{where}\lambda} = \{ {{\begin{matrix}{\min ( {\beta,\varphi} )} & {{{if}\mspace{14mu} \gamma} \geq 0} \\0 & {otherwise}\end{matrix}\beta} = {{\lfloor \lbrack \frac{{MCS}_{report} - {lastMCS}_{alloc}}{2} \rbrack^{+} \rfloor \gamma} = {{{\mu {\sum\limits_{i}^{\;}\; 1_{\{{{CRC}_{i}{pass}}\}}}} - {\sum\limits_{i}^{\;}\; {1_{\{{{CRC}_{i}{fail}}\}}\mu}}} = {{0.11\varphi} = 3}}}} } } } $

In this example, lastMCS_(alloc) corresponds to the last MCS allocatedby the BS before the present UE CQI report, while MCS_(report) refers tothe MCS estimate obtained by the UE by mapping the previous CQI reportto an MCS value. CRC, represents the detection of the i-th newtransmission of DL PDSCH since tune-back. If DL transmissions are notscheduled, this may imply MCS and CRC information may not yet beavailable at the UE, hence the nominal α=1 used in this case, in asimilar manner and for similar reasons as during the first period oftime.

The value μ may represent the target BLER; in this example, a value of0.11 may be used for a 10% BLER target. Other values could be used asdesired, e.g., for other target BLERs. The value φ may be used as anoffset limit, in order to avoid grossly misrepresenting the CQI to theBS by using a very large CQI offset; while the value 3 is provided as anexample, other values could easily be used.

If desired, an alternative calculation of the CQI offset α may beperformed as follows:

let[x]⁺ = max (0, x) $1_{\{{CRCfail}\}} = \{ {{\begin{matrix}1 & {{if}\mspace{14mu} {CRC}\mspace{14mu} {fails}} \\0 & {otherwise}\end{matrix}1_{\{{CRCpass}\}}} = \{ {{\begin{matrix}1 & {{if}\mspace{14mu} {CRC}\mspace{14mu} {passes}} \\0 & {otherwise}\end{matrix}{then}\alpha} = \{ {{\begin{matrix}1 & {{if}\mspace{14mu} {no}\mspace{14mu} {DL}\mspace{14mu} {TX}\mspace{14mu} {scheduled}\mspace{14mu} {since}\mspace{14mu} {tune}\text{-}{back}} \\\lambda & {otherwise}\end{matrix}{where}\lambda} = {{{\min ( {\beta,\gamma,\varphi} )}\beta} = {{\lfloor \lbrack \frac{{MCS}_{report} - {lastMCS}_{alloc}}{2} \rbrack^{+} \rfloor \gamma} = {{\lfloor \lbrack {\varphi - {\sum\limits_{i}^{\;}\; 1_{\{{{CRC}_{i}{fail}}\}}} + {\mu {\sum\limits_{i}^{\;}\; 1_{\{{{CRC}_{i}{pass}}\}}}}} \rbrack^{+} \rfloor \mu} = {{0.11\varphi} = 3}}}}} } } $

In this example, the calculation may be similar, but may be moreaggressive in selecting the CQI offset α, in particular with respect tothe BLER.

By using the CQI offset α during the second period of time, the UE 506may recover an appropriate MCS for the actual channel conditions morerapidly than if no CQI offset were used. At the same time, by usingappropriate checks and limits to ensure that a CQI offset is notover-applied or applied when the allocated MCS is appropriate to theactual channel conditions, the potential negative consequences of the UE506 manipulating MCS allocation may be minimized.

As noted above, the second period of time may extend for a duration δ.The value of δ may be selected such that sufficient time may have passedfor the BS 506 to stop using BLER estimates from the period of timewhile the UE 506 was tuned away, in some embodiments. This may mean thatthe value of δ may be dynamically determined by the UE 506 in someembodiments, e.g., based on an estimation of the length of thecommunication interruption (e.g., the tune-away or fade) and/orknowledge of the BLER estimation algorithm at the BS 502.

After the second period of time has ended (e.g., after the timer Treaches T=T_(WAIT)+δ), the UE 506 may cease using a CQI offset ingenerating the CQI report, and may simply use the measuredCQI_(no-offset) value. From this point forward (e.g., until a nexttune-away or other interruption in communication), it may be the casethat the allocated MCS appropriately reflects the actual channelconditions, and so there would be little or no utility in continuing tomodify the CQI report with a CQI offset. However, in some embodiments,if the UE 506 tunes-away regularly (e.g., according to the schedule of a1xRTT paging channel), the UE 506 may perform the method to rapidlyrecover appropriate MCS allocations each time the UE 506 tunes-back toLTE.

Embodiments of the present disclosure may be realized in any of variousforms. For example some embodiments may be realized as acomputer-implemented method, a computer-readable memory medium, or acomputer system. Other embodiments may be realized using one or morecustom-designed hardware devices such as ASICs. Still other embodimentsmay be realized using one or more programmable hardware elements such asFPGAs.

In some embodiments, a non-transitory computer-readable memory mediummay be configured so that it stores program instructions and/or data,where the program instructions, if executed by a computer system, causethe computer system to perform a method, e.g., any of a methodembodiments described herein, or, any combination of the methodembodiments described herein, or, any subset of any of the methodembodiments described herein, or, any combination of such subsets.

In some embodiments, a device (e.g., a UE) may be configured to includea processor (or a set of processors) and a memory medium, where thememory medium stores program instructions, where the processor isconfigured to read and execute the program instructions from the memorymedium, where the program instructions are executable to implement anyof the various method embodiments described herein (or, any combinationof the method embodiments described herein, or, any subset of any of themethod embodiments described herein, or, any combination of suchsubsets). The device may be realized in any of various forms.

Although the embodiments above have been described in considerabledetail, numerous variations and modifications will become apparent tothose skilled in the art once the above disclosure is fully appreciated.It is intended that the following claims be interpreted to embrace allsuch variations and modifications.

What is claimed is:
 1. A method for a user equipment (UE) device tomanipulate downlink throughput after a communication interruption, themethod comprising: communicating with a base station (BS) according to afirst wireless communication protocol; determining that an interruptionto communication between the UE and the BS has occurred; resumingcommunicating with the BS according to the first wireless communicationprotocol after the interruption, wherein resuming communicating with theBS comprises: generating first channel quality information based on afirst one or more channel quality measurements; transmitting the firstchannel quality information to the BS; receiving first downlink channelinformation from the BS, wherein the first downlink channel informationreflects a first allocated downlink throughput, wherein the firstdownlink throughput is allocated by the BS based at least in part on thefirst channel quality information received from the UE; generatingsecond channel quality information based on a second one or more channelquality measurements; generating an offset for the second channelquality information, wherein the offset is generated based at least inpart on the first downlink channel information in order to modify afuture downlink throughput allocation; and transmitting the secondchannel quality information modified by the offset to the BS.
 2. Themethod of claim 1, further comprising: estimating a downlink error rate;wherein the offset is generated based at least in part on the estimateddownlink error rate and a target downlink error rate.
 3. The method ofclaim 1, further comprising: determining whether downlink data blockssince resuming communicating with the BS are successfully orunsuccessfully received; wherein the offset is generated based at leastin part on the determination of whether downlink data blocks sinceresuming communicating with the BS are successfully or unsuccessfullyreceived.
 4. The method of claim 1, wherein the first downlink channelinformation comprises a modulation and coding scheme (MCS) allocation,wherein the MCS allocation specifies a type of modulation and coding tobe used in downlink communications between the BS and the UE.
 5. Themethod of claim 4, wherein the BS uses channel quality informationreceived from the UE to determine the MCS allocation, wherein bymodifying the second channel quality information by the offset, the UEmanipulates a future MCS allocation.
 6. The method of claim 4, furthercomprising: estimating an MCS allocation based on the first channelquality information; calculating a difference between the MCS allocationreceived from the BS and the estimated MCS allocation; wherein theoffset is generated based at least in part on the difference between theMCS allocation received from the BS and the estimated MCS allocation. 7.A user equipment (UE) device, comprising: a radio, comprising one ormore antennas for performing wireless communication; a processor; acomputer accessible memory medium comprising program instructions forresuming communicating with a BS according to a first wirelesscommunication protocol after a communication interruption, wherein theprogram instructions are executable by the processor to: generate firstchannel quality information; transmit the first channel qualityinformation to the BS; receive a first modulation and coding scheme(MCS) allocation from the BS, wherein the first MCS allocation is basedat least in part on the first channel quality information; generatesecond channel quality information, wherein the second channel qualityinformation comprises an offset configured to modify a second MCSallocation; and transmit the second channel quality information to theBS.
 8. The UE device of claim 7, wherein the UE device is configured tocommunicate according to either of the first wireless communicationprotocol or a second wireless communication protocol using the radio;wherein the communication interruption comprises the UE device using theradio to communicate according to the second wireless communicationprotocol for a period of time.
 9. The UE device of claim 7, wherein thecommunication interruption occurred for a first period of time; whereinthe program instructions are further executable to iteratively receiveMCS allocations and generate channel quality information comprisingoffsets configured to modify future MCS allocations for a second periodof time, wherein the duration of the second period of time is based atleast in part on the duration of the first period of time.
 10. The UEdevice of claim 7, wherein the first channel quality informationcomprises a first offset configured to modify the first MCS allocation,wherein the first offset is a fixed offset; wherein the offset comprisedin the second channel quality information comprises a second offset,wherein the second offset is dynamically selected based at least in parton the first MCS allocation.
 11. The UE device of claim 10, wherein thesecond offset is also selected based at least in part on the firstchannel quality information.
 12. The UE device of claim 7, wherein theprogram instructions are further executable to: estimate an appropriateMCS for the UE based on the first channel quality information; calculatea difference between the estimated appropriate MCS and the first MCSallocation; generate the offset based at least in part on the differencebetween the estimated appropriate MCS and the first MCS allocation. 13.The UE device of claim 7, wherein the program instructions are furtherexecutable to: determine whether downlink data blocks since resumingcommunicating with the BS are successfully or unsuccessfully received;wherein the offset is generated based at least in part on thedetermination of whether downlink data blocks since resumingcommunicating with the BS are successfully or unsuccessfully received.14. The UE device of claim 13, wherein the program instructions areexecutable to determine whether downlink data blocks since resumingcommunicating with the BS are successfully or unsuccessfully receivedbased on cyclic redundancy check (CRC) information comprised in thedownlink data blocks.
 15. A non-transitory computer accessible memorymedium comprising program instructions for a user equipment (UE) deviceto manipulate modulation and coding scheme (MCS) selection after acommunication interruption, wherein the program instructions areexecutable to: communicate with a first base station (BS) according to afirst wireless communication protocol; determine that an interruption tocommunication between the UE and the first BS has occurred; resumecommunicating with the BS according to the first wireless communicationprotocol after the interruption, wherein in order to resumecommunicating with the first BS, the program instructions are furtherexecutable to: generate first channel quality information, wherein thefirst channel quality information is based on a first one or morechannel quality measurements, wherein the first channel qualityinformation is also based on a first offset, wherein the first offset isconfigured to manipulate a MCS allocation by the first BS based ondetermining that the interruption to communication between the UE andthe first BS has occurred; transmit the first channel qualityinformation to the first BS.
 16. The memory medium of claim 15, whereinin order to resume communicating with the BS, the program instructionsare further executable to: receive a first MCS allocation from the firstBS, wherein the first MCS allocation is based at least in part on thefirst channel quality information; estimate an appropriate first MCSallocation based on the first channel quality information; generatesecond channel quality information, wherein the second channel qualityinformation is based on a second one or more channel qualitymeasurements, wherein the second channel quality information is alsobased on a second offset, wherein the second offset is configured tomanipulate a next MCS allocation by the first BS based on a differencebetween the estimated appropriate first MCS allocation and the receivedfirst MCS allocation; transmit the second channel quality information tothe first BS.
 17. The memory medium of claim 15, wherein the programinstructions are further executable to: determine whether downlink datablocks since resuming communicating with the first BS are successfullyor unsuccessfully received; wherein the second offset is based at leastin part on the determination of whether downlink data blocks sinceresuming communicating with the first BS are successfully orunsuccessfully received.
 18. The memory medium of claim 15, wherein theinterruption to communication between the UE and the first BS comprisesa long fade.
 19. The memory medium of claim 18, wherein the programinstructions are further executable to: determine that the long fade hasended; wherein the program instructions are configured to resumecommunicating with the first BS based on determining that the long fadehas ended.
 20. The memory medium of claim 15, wherein the programinstructions are further executable to communicate with base stationsaccording to a second wireless communication protocol; wherein theinterruption to communication between the UE and the first BS comprisesa period of time during which the UE communicates with a second BSaccording to the second wireless communication protocol.
 21. A methodfor a wireless user equipment (UE) device to manipulate modulation andcoding scheme (MCS) selection after a communication interruption, themethod comprising: communicating with a first base station (BS)according to a first wireless communication protocol at a first time;communicating with a second BS according to a second wirelesscommunication protocol at a second time, wherein communicating with thesecond BS at the second time comprises an interruption to communicationwith the first BS; resuming communicating with the first BS at a thirdtime, wherein resuming communicating with the BS comprises: generatingand transmitting a first CQI value, wherein the first CQI value isgenerated based on a first channel quality estimate; receiving an MCSallocation from the BS, wherein the MCS allocation is selected by the BSbased at least in part on the first CQI value and at least in part onone or more block error rate estimates from the second time; generatingan MCS estimation based the first CQI value; generating and transmittinga second CQI value, wherein the second CQI value is generated based on asecond channel quality estimate and a CQI offset, wherein the CQI offsetis based on a difference between the MCS allocation and the MCSestimation.
 22. The method of claim 21, wherein the one or more blockerror rate estimates from the second time reflect the interruption tocommunication.
 23. The method of claim 21, wherein the CQI offset isalso based on cyclic redundancy check (CRC) information in data blocksreceived by the UE.
 24. The method of claim 21, wherein generating andtransmitting the first CQI value are performed prior to receiving anyMCS allocations from the BS since resuming communicating with the firstBS at the third time.
 25. A method for a wireless user equipment (UE)device to manipulate modulation and coding scheme (MCS) selection afterperiodic communication interruptions, the method comprising: operatingaccording to a first radio access technology (RAT), wherein operatingaccording to the first RAT comprises generating and transmitting channelquality reports to a base station (BS) according to the first RAT,wherein the channel quality reports are used by the BS to select an MCSallocation for the UE; operating according to a second RAT on each of aplurality of occasions in a periodic manner, wherein each occasioncomprises an interruption to operating according to the first RAT;resuming operating according to the first RAT after each interruption;wherein during a period of time after each interruption, at least onechannel quality reports is generated using an offset configured tomanipulate selection of the MCS allocation; wherein while operatingaccording to the first RAT at times other than the period of time aftereach interruption, channel quality reports are generated not usingoffsets configured to manipulate MCS allocation.
 26. The method of claim25, wherein during the period of time after each interruption, aplurality of channel quality reports are generated using offsetsconfigured to manipulate selection of the MCS allocation;
 27. The methodof claim 25, wherein the method further comprises: determining a lengthof the period of time after each respective interruption based on alength of the respective interruption.